1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing minute metallic spheres suitably used for forming a ball bump on an electrode of a semiconductor device, a printed circuit board, or the like.
2. Description of the Related Art
As methods of manufacturing minute metallic spheres within low-melting temperature, there are atomization method and a method of obtaining metallic spheres by dipping a metallic piece made into a predetermined volume in advance, in a heated liquid.
Besides, in the method described in Japanese Patent Application Laid-open No. 4-74801, a molten metal is extruded from very fine particles in a liquid heated to a temperature more than the melting point of the metal.
Although a large quantity of metallic particles can be obtained for a short time by the atomization method, it is difficult to make the shapes of the particles uniform in sphere and into an aimed size, and the yield becomes very bad. By the method of dropping a metallic piece in the heated liquid, it can be made into a substantially complete sphere by surface tension. But, for making the sizes of metallic pieces to be dropped, uniform in advance, there are some required processes of press-punching a plate made very thin by rolling or the like, or of making into a fine line with a die or the like and accurately cutting with a cutter or the like.
Besides, in that described in the Japanese Patent Application Laid-open No. 4-74801, the interior of a vertical tube is filled with a natural oil or the like, and a zone or a region having a temperature range more than the melting point of a metal is provided by a heater attached to the upper portion of the vertical tube. And, a low-melting alloy supply tube to which a fine grating is attached in that region, is stood such that the fine grating is at the lower position. A lump of a low-melting alloy is inserted in the low-melting alloy supply tube and molten, and an inert gas is fed through the upper portion of the low-melting alloy supply tube. Molten alloy is extruded from the fine grating by the pressure of the gas and made into particles, and they become spherical shape by passing through the temperature inclination of the vertical tube.
However, in the method described in this official gazette, the relation between the grating size and the pressurizing force, or the like, is unknown. In any case, the shape of a particle is made by the surface tension in a delicate balance relation to such a factor. In this method, so-called duplex grain can not be avoided.
In consideration of such an actual condition, the present invention aims to provide a method and an apparatus for manufacturing minute metallic spheres, capable of accurately and efficiently manufacturing minute metallic spheres of a predetermined size.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, wherein a minute metallic sphere is formed by injecting a molten metal in a gauger of a predetermined volume to measure, and discharging the measured molten metal from the gauger to solidify.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, including a step of heating and melting, a metal to form a metallic sphere, and injecting the molten metal in a gauger, a step of taking by rubbing the molten metal injected in said gauger by a predetermined volume to measure, and a step of discharging the measured molten metal from the gauger, and cooling the molten metal to a temperature less than the melting point to solidify.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, comprising a heating means for heating and melting a metal to form a metallic sphere, a measurement means for measuring the injected molten metal into a predetermined volume, and a cooling means for cooling said molten metal discharged from said gauger, to a temperature less than the melting point.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, wherein a minute metallic sphere is formed by discharging a molten metal from an opening portion, and dividing said molten metal discharged from said opening portion into each predetermined volume.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, having a step of heating and melting a metal to form a metallic sphere, and discharging the molten metal from an opening portion, a step of dividing said molten metal discharged from said opening portion into each predetermined volume, and a step of cooling said molten metal divided to a temperature less than the melting point to solidify.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, comprising a heating means for heating and melting a metal to form a metallic sphere, a means for discharging the molten metal from a predetermined opening portion, a division means for dividing said molten metal having passed through said opening part, and a cooling means for cooling said molten metal divided by said division means, to a temperature less than the melting point.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, including a step of heating and melting a metal to form a metallic sphere, and injecting the molten metal in a measurement means by pressurizing, a step of cutting by rubbing the molten metal injected in the measurement means by a predetermined volume to measure, and a step of discharging the measured molten metal from the measurement means by a fluid pressure, and cooling the molten metal to a temperature less than the melting point to solidify.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres for manufacturing minute metallic spheres of a predetermined size, comprising a heating means for heating and melting a metal to form a metallic sphere, a metal supply means for pressurizing and supplying the molten metal by the heating means, a measurement means supported so as to be rotatable relatively to said metal supply means, for measuring the injected molten metal into a predetermined volume by its rotational action, and a cooling means for cooling said molten metal discharged from said measurement means, to a temperature less than the melting point.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, wherein it has one or a plurality of cooling means in the lower part of said measurement unit, and a lower portion of said oil vessel is cooled.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, wherein one or a plurality of regions in the lower part of said oil vessel is cooled, and the oil in each region is set and kept at a predetermined temperature.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, having one or a plurality of moving-flow regulation means for physically regulating a convection of said oil in the oil vessel in the lower part of said measurement unit.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, wherein a convection of the oil in the oil vessel is physically regulated in one or a plurality of portions in the lower part of said measurement unit, and the oil in each region regulated is set and kept at a predetermined temperature.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, having a dispersion means for dispersing the molten metal, in the lower part of said measurement unit.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, wherein, in the lower part of said measurement unit, the molten metal discharged from the measurement unit, is dispersed.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of an oil vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in an oil, comprising a molten metal supply apparatus for supplying a molten metal from which inclusions have been removed, to the measurement unit.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of a vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in a cooling medium put in the vessel, wherein said cooling medium comprises an inert high-molecular liquid, an inert high-molecular steam and an inert gas.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of a vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in a cooling medium put in the vessel, wherein said cooling medium comprises an oil, and an inert high-molecular liquid put in the lower part of the oil.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres having a measurement unit in an upper portion of a vessel disposed vertically in which a cooling medium is put, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in the cooling medium put in the vessel, wherein an inert high-molecular liquid, an inert high-molecular steam and an inert gas are used as said cooling medium, and said molten metal is cooled by said cooling medium to solidify.
A manufacturing apparatus of minute metallic spheres of the present invention is a manufacturing apparatus of minute metallic spheres having a measurement unit in an upper portion of a vessel disposed vertically, for forming a minute metallic sphere by solidifying a molten metal discharged from this measurement unit, in a cooling medium put in the vessel, wherein the viscosity of said cooling medium is kept into 2 cSt to 20 cSt at the temperature of 200xc2x0 C. at which said molten metal is melted, and the dropping speed of said molten metal in said cooling medium is decreased by the viscosity of said cooling medium.
A manufacturing method of minute metallic spheres of the present invention is a manufacturing method of minute metallic spheres in which a measured molten metal is discharged in a vessel disposed vertically in which a cooling medium is put, and a minute metallic sphere is formed by solidifying said molten metal in said cooling medium, wherein the viscosity of said cooling medium is kept into 2 cSt to 20 cSt at the temperature of 200xc2x0 C. at which said molten metal is melted, and the dropping speed of said molten metal in said cooling medium is decreased by the viscosity of said cooling medium.
A semiconductor device according to the present invention is a semiconductor device in which a semiconductor chip and a substrate are electrically connected by minute metallic spheres of a predetermined size, wherein said minute metallic spheres are formed by injecting a molten metal in a gauger of a predetermined volume to measure, and discharging the measured molten metal from the gauger to solidify.
A semiconductor device according to the present invention is a semiconductor device in which a semiconductor chip and a substrate are electrically connected by minute metallic spheres of a predetermined size, wherein said minute metallic spheres are manufactured by a method including a step of heating and melting a metal to form a metallic sphere, and injecting the molten metal in a gauger, a step of cutting by rubbing the molten metal injected in said gauger by a predetermined volume to measure, and a step of discharging the measured molten metal from the gauger, and cooling the molten metal to a temperature less than the melting point to solidify.
According to the present invention, by heating and melting a metal to form a metallic sphere, by a heating means, injecting this molten metal in a gauger of a predetermined volume, and sliding this gauger in contact, it can be measured accurately. Further, this measured molten metal is discharged from the gauger as it is in the molten state, and cooled by a cooling means to a temperature less than the melting point. The molten metal after measurement solidifies into a sphere by surface tension in the cooling process, and thereby, a minute metallic sphere of a predetermined size and shape can be obtained with high accuracy.
According to the present invention, minute metallic spheres of this kind can be manufactured accurately and efficiently. Although controllability for making the diameters of metallic spheres uniform and mass-productivity in manufacture are not compatible hitherto, mass production can be made efficiently with high dimensional accuracy, using the present invention. Because metallic spheres of an aimed diameter can thus be obtained efficiently, the productivity can be improved considerably.
According to the present invention, minute metallic spheres of a predetermined size can be manufactured accurately and efficiently. Accordingly, metallic spheres having a desired diameter can be obtained efficiently, and the productivity can be improved considerably.
According to the present invention, a metal to form a metallic sphere is heated and melted by a heating means, and this molten metal is injected in a measurement means of a predetermined volume. In this case, it is pressurized and supplied at a high pressure from one side of the measurement means, and the other side opposite to it is set to a low pressure, and, by sliding this measurement means in contact, it can be measured accurately. Further, this measured molten metal is discharged from the measurement means as it is in the molten state, and cooled by a cooling means to a temperature less than the melting point. The molten metal after measurement solidifies into a sphere shape by surface tension in the cooling process, and thereby, a minute metallic sphere of a predetermined size and shape can be obtained with high accuracy.
According to the present invention, by setting/keeping properly the oil temperature in an oil vessel, and cooling/solidifying a molten metal, a minute metallic sphere of good quality can be obtained. Besides, by dispersing the molten metal, the temperature distribution is made stable, and molten metals are prevented from uniting with each other, and a minute metallic sphere of good quality can be formed efficiently.
According to the present invention, by discharging a molten metal in an inert high-molecular liquid as a cooling medium, cleaning after solidifying can easily be performed, and it becomes possible to simplify the cleaning process.
According to the present invention, it becomes possible to lower the dropping speed of a discharged molten metal. Accordingly, it becomes possible to manufacture minute metallic spheres whose sphericity has been improved.
According to the present invention, by forming minute metallic spheres by the above-described manufacturing methods and apparatus, and using them for connecting a chip and a substrate in a semiconductor device, miniaturization of the package of the semiconductor device can be attained, and the cost can be lowered.